Engineering RNA export for measurement and manipulation of living cells.

A system for programmable export of RNA molecules from living cells would enable both non-destructive monitoring of cell dynamics and engineering of cells capable of delivering executable RNA programs to other cells. We developed genetically encoded cellular RNA exporters, inspired by viruses, that efficiently package and secrete cargo RNA molecules from mammalian cells within protective nanoparticles. Exporting and sequencing RNA barcodes enabled non-destructive monitoring of cell population dynamics with clonal resolution. Further, by incorporating fusogens into the nanoparticles, we demonstrated the delivery, expression, and functional activity of exported mRNA in recipient cells. We term these systems COURIER (controlled output and uptake of RNA for interrogation, expression, and regulation). COURIER enables measurement of cell dynamics and establishes a foundation for hybrid cell and gene therapies based on cell-to-cell delivery of RNA.

Food as medicine? Exploring the impact of providing healthy foods on adherence and clinical and economic outcomes.

Background: Chronic disease prevalence is increasing. Adherence to dietary guidelines is low (<50%) despite positive impacts in disease progression, clinical outcomes, and medical costs. It is important to summarize the impact of providing medically-tailored meals to patients on adherence rates, clinical outcomes, and potential economic outcomes. Methods: A systematic review was conducted to identify, extract, and appraise food-provision studies from January 1, 2013-May 1, 2018 for heart disease, diabetes (DM), and chronic kidney disease (CKD). The key findings related to adherence and clinical outcomes were compiled. Published literature was utilized to determine the economic impact of key clinical outcomes. Results: Across diseases, 100 articles (N = 43,175 patients) were included. Dietary adherence was considered "compliant" or ≥ 90% consistently. Significant (p < 0.05) clinical outcomes included 5-10% LDL reduction, 4-11 mmHg SBP reduction, 30% reduction in metabolic syndrome prevalence, 3-5% weight reduction, 56% lower CKD mortality rates, and increased dialysis-free time (2 years:50%, 5 years:25%, calculated cost savings of 80.6-94.3%). Literature review showed these outcomes would result in decreased: cardiovascular (CV) event risk (20-30% reduction: $5-11 billion annually), hospitalization costs ($1-8 billion), and dialysis rates (25-50% reduction: $14-29 billion annually). For heart failure patients, results include: 16% fewer readmissions (saving $234,096 per 100 patients) and a 38-day shorter length of stay (saving $79,425 per hospitalization). Conclusion: Providing medically-tailored meals significantly increases dietary adherence above 90% and allows patients to realize significantly better chronic disease control. Through this, patients could experience fewer complications (CV events, hospital readmissions and dialysis), resulting in significant annual US healthcare cost reduction of $27-48 billion.

Enhanced Hybridization Selectivity Using Structured GammaPNA Probes.

High affinity nucleic acid analogues such as gammaPNA (γPNA) are capable of invading stable secondary and tertiary structures in DNA and RNA targets but are susceptible to off-target binding to mismatch-containing sequences. We introduced a hairpin secondary structure into a γPNA oligomer to enhance hybridization selectivity compared with a hairpin-free analogue. The hairpin structure features a five base PNA mask that covers the proximal five bases of the γPNA probe, leaving an additional five γPNA bases available as a toehold for target hybridization. Surface plasmon resonance experiments demonstrated that the hairpin probe exhibited slower on-rates and faster off-rates (i.e., lower affinity) compared with the linear probe but improved single mismatch discrimination by up to a factor of five, due primarily to slower on-rates for mismatch vs. perfect match targets. The ability to discriminate against single mismatches was also determined in a cell-free mRNA translation assay using a luciferase reporter gene, where the hairpin probe was two-fold more selective than the linear probe. These results validate the hairpin design and present a generalizable approach to improving hybridization selectivity.

Culinary Medicine: Advancing a Framework for Healthier Eating to Improve Chronic Disease Management and Prevention.

Unsustainable increases in the prevalence and costs of chronic disease in the United States call for low-cost, high-impact interventions that can be readily incorporated into people's daily lives. Culinary medicine is one such intervention. As a practical discipline, culinary medicine integrates the art of preparing, cooking, and presenting food with the science of medicine to achieve desired health outcomes. This article describes how the underpinnings and components of culinary medicine enhance existing nutrition interventions. Evidence of improved well-being and reduced resource utilization as the result of culinary medicine interventions is compiled for easy reference by health care organizations, medical professionals, people living with or at risk for chronic disease, food industry specialists, and payers in both the public and private sectors. Suggestions for individual and organizational implementation of culinary medicine strategies are offered with a proposed lexicon for continued development of the field.

Incorporating Site-less Clinical Trials Into Drug Development: A Framework for Action.

PURPOSE: Options for leveraging available telemedicine technologies, ranging from simple webcams and telephones to smartphone apps and medical-grade wearable sensors, are evolving faster than the culture of clinical research. Until recently, most clinical trials relied on paper-based processes and technology. This cost- and labor-intensive system, while slowly changing, remains an obstacle to new drug development. Alternatives that use existing tools and processes for collecting real-world data in home settings warrant closer examination. METHODS: The site-less clinical research organization (CRO) model, whereby pharmacists or other health care professionals provide useful and timely counseling for protocol compliance by regular phone and videoconferencing sessions, is a flexible approach to managing clinical trial participants directly from their homes. An expert panel, including clinical specialists in metabolic or neurodegenerative diseases, health information technology and CRO innovators, and the pharmaceutical industry, met in Dallas, Texas, December 2016, to discuss advancing avenues for site-less CRO and other remote clinical trial practices, taking into account investigator, sponsor, and regulatory perspectives. FINDINGS: Real-time "site-less" management of clinical trials can augment traditional research and development methods by providing data from a broader, more diverse group of patients in real-world practice settings. This methodology also helps to proactively identify safety profile and operational issues. Current use of site-less CRO practices constitutes an important bridge to alternative trial models, including "large simple trials" that strive to answer one or two questions using data derived from representative patient populations treated in typical clinical settings. IMPLICATIONS: Site-less CROs offer a working example of how remote technologies and in-home monitoring methods can address shortcomings of conventional drug development. This model maximizes time and cost, as well as potentially earlier identification of adverse events. Coordinated communication among investigators, sponsors, regulators, and patients will be needed to develop standardized strategies for incorporating site-less CROs into current and future study design.

Frequency and Impact of Pharmacist Interventions in Clinical Trial Patients With Diabetes.

PURPOSE: The objective of this study was to describe the interventions and impact made by pharmacists during clinical trials. METHODS: A specialty contract research organization that used clinical trial research pharmacists to communicate with patients to support clinical trial protocol adherence, retention, and health outcomes performed a retrospective, descriptive analysis of 12 clinical trials that involved 2 noninsulin glucose-lowering medications. Pharmacists called study participants at specific timepoints during the trials as per protocol. During each telephone call, the number and types of interventions were documented. Descriptive statistics (frequencies) were performed to determine the number and type of interventions by call and by patient across all noninsulin glucose-lowering medication drug A and drug B studies. FINDINGS: Overall, 25,829 calls were made across all studies. Of these calls, 11,765 calls (45.5%) had at least one intervention that involved 3573 patients (92.3%). The most frequent interventions addressed adverse events (3774 [14.6%]), protocol violations for medication use (3341 [12.9%]), concurrent medications (1630 [5.9%]), and miscellaneous concerns (1269 [4.6%]). The greatest numbers of interventions were high-impact interventions (4772 [18.5%]) (eg, serious adverse events) that would seriously affect trial outcomes and patient adherence. IMPLICATIONS: Pharmacists were able to identify, support, and address multiple types of interventions related to medication management during clinical trials, including those related to concurrent medication use, adverse events, and other medication-related issues. These pharmacist interventions can result in better patient outcomes and, ultimately, more reliable study results for review and approval by regulatory agencies.

A Retrospective Chart Review of Two Different Insulin Administration Systems on Glycemic Control in Older Adults in Long-Term Care.

The current retrospective chart review compared glycemic control and cost impact of two insulin administration systems, V-Go® versus usual care with standard of care (SOC) insulin injections, in eight patients residing in a nursing home (NH). A total of 1,937 blood glucose (BG) values were collected over 61 days. Significant improvements were observed for the V-Go versus SOC group in time in range 100 mg/dL to 200 mg/dL (V-Go 59.09% vs. SOC 34.02%; p < 0.001), reduced BG fluctuations as measured by standard deviation (V-Go 61.2 vs. SOC 92.1; p < 0.001), and improved mean daily BG (V-Go 159.38 mg/dL vs. SOC 223.86 mg/dL; p < 0.001). The estimated A1c change, calculated from BG values, decreased from 8.9% to 7.2% in the V-Go group and increased from 9.0% to 9.4% in the SOC group. Compared to SOC, use of V-Go decreased the mean time for insulin administration by nursing staff by 26.3 minutes per patient per day and associated labor costs by $328.75 per patient per month. Insulin administration with V-Go may improve glycemic control and reduce administration costs compared to existing care in the NH setting. [Journal of Gerontological Nursing, 43(1), 10-16.].

RNA G-Quadruplex Invasion and Translation Inhibition by Antisense γ-Peptide Nucleic Acid Oligomers.

We have examined the abilities of three complementary γ-peptide nucleic acid (γPNA) oligomers to invade an RNA G-quadruplex and potently inhibit translation of a luciferase reporter transcript containing the quadruplex-forming sequence (QFS) within its 5'-untranslated region. All three γPNA oligomers bind with low nanomolar affinities to an RNA oligonucleotide containing the QFS. However, while all probes inhibit translation with low to midnanomolar IC50 values, the γPNA designed to hybridize to the first two G-tracts of the QFS and adjacent 5'-overhanging nucleotides was 5-6 times more potent than probes directed to either the 3'-end or internal regions of the target at 37 °C. This position-dependent effect was eliminated after the probes and target were preincubated at an elevated temperature prior to translation, demonstrating that kinetic effects exert significant control over quadruplex invasion and translation inhibition. We also found that antisense γPNAs exhibited similarly potent effects against luciferase reporter transcripts bearing QFS motifs having G2, G3, or G4 tracts. Finally, our results indicate that γPNA oligomers exhibit selectivity and/or potency higher than those of other antisense molecules such as standard PNA and 2'-OMe RNA previously reported to target G-quadruplexes in RNA.

Effects of inhaled anesthetic isoflurane on long-term potentiation of CA3 pyramidal cell afferents in vivo.

Isoflurane is a preferred anesthetic, due to its properties that allow a precise concentration to be delivered continually during in vivo experimentation. The major mechanism of action of isoflurane is modulation of the γ-amino butyric acid (GABA(A)) receptor-chloride channel, mediating inhibitory synaptic transmission. Animal studies have shown that isoflurane does not cause cell death, but it does inhibit cell growth and causes long-term hippocampal learning deficits. As there are no studies characterizing the effects of isoflurane on electrophysiological aspects of long-term potentiation (LTP) in the hippocampus, it is important to determine whether isoflurane alters the characteristic responses of hippocampal afferents to cornu ammonis region 3 (CA3). We investigated the effects of isoflurane on adult male rats during in vivo induction of LTP, using the mossy fiber pathway, the lateral perforant pathway, the medial perforant pathway, and the commissural CA3 (cCA3) to CA3, with intracranial administration of Ringer's solution, naloxone, RS-aminoindan-1, 5-dicarboxylic acid (AIDA), or 3-[(R)-2-carboxypiperazin-4-yl]-propo-2-enyl-1-phosphonic acid (CPP). Then, we compared these responses to published electrophysiological data, using sodium pentobarbital as an anesthetic, under similar experimental conditions. Our results showed that LTP was exhibited in animals anesthetized with isoflurane under vehicle conditions. With the exception of AIDA in the lateral perforant pathway, the defining characteristics of the four pathways appeared to remain intact, except for the observation that LTP was markedly reduced in animals anesthetized with isoflurane compared to those anesthetized with sodium pentobarbital. The results suggest that isoflurane may affect amplitude through activation of GABA(A) receptors or mechanisms important to LTP in CA3 afferent fibers.

Brain Circuits of Methamphetamine Place Reinforcement Learning: The Role of the Hippocampus-VTA Loop.

The reinforcing effects of addictive drugs including methamphetamine (METH) involve the midbrain ventral tegmental area (VTA). VTA is primary source of dopamine (DA) to the nucleus accumbens (NAc) and the ventral hippocampus (VHC). These three brain regions are functionally connected through the hippocampal-VTA loop that includes two main neural pathways: the bottom-up pathway and the top-down pathway. In this paper, we take the view that addiction is a learning process. Therefore, we tested the involvement of the hippocampus in reinforcement learning by studying conditioned place preference (CPP) learning by sequentially conditioning each of the three nuclei in either the bottom-up order of conditioning; VTA, then VHC, finally NAc, or the top-down order; VHC, then VTA, finally NAc. Following habituation, the rats underwent experimental modules consisting of two conditioning trials each followed by immediate testing (test 1 and test 2) and two additional tests 24 h (test 3) and/or 1 week following conditioning (test 4). The module was repeated three times for each nucleus. The results showed that METH, but not Ringer's, produced positive CPP following conditioning each brain area in the bottom-up order. In the top-down order, METH, but not Ringer's, produced either an aversive CPP or no learning effect following conditioning each nucleus of interest. In addition, METH place aversion was antagonized by coadministration of the N-methyl-d-aspartate (NMDA) receptor antagonist MK801, suggesting that the aversion learning was an NMDA receptor activation-dependent process. We conclude that the hippocampus is a critical structure in the reward circuit and hence suggest that the development of target-specific therapeutics for the control of addiction emphasizes on the hippocampus-VTA top-down connection.

Local pretreatment with the cannabinoid CB1 receptor antagonist AM251 attenuates methamphetamine intra-accumbens self-administration.

The endocannabinoid system is a potential target for therapeutic intervention of substance abuse. Cannabinoid CB1 receptor antagonist decreases intravenous methamphetamine self-administration in animal models. This study examined whether the nucleus accumbens (NAcc) is a site of interaction between methamphetamine and the CB1 receptor antagonist AM251. Male Sprague-Dawley rats were trained to lever press and then were surgically implanted with a guide cannula into the right NAcc. Rats were allowed one week to recover and then AM251 (0.1 or 1.0 µg/µL) was reverse dialyzed directly into the NAcc prior to methamphetamine (10 µg/µL) intra-accumbens self-administration. AM251 (1.0 µg/µL) reduced methamphetamine self-administration while AM251 (0.1 µg/µL) had an intermediary effect. The mechanism of self-administration attenuation is not known but could be mediated by AM251 affecting the negative feedback from the NAcc to the ventral tegmental area (VTA). This study provides evidence that the endocannabinoid system is involved with rewarding effects of methamphetamine and suggests a possible therapeutic intervention for methamphetamine abuse.

Local hippocampal methamphetamine-induced reinforcement.

Drug abuse and addiction are major problems in the United States. In particular methamphetamine (METH) use has increased dramatically. A greater understanding of how METH acts on the brain to induce addiction may lead to better therapeutic targets for this problem. The hippocampus is recognized as an important structure in learning and memory, but is not typically associated with drug reinforcement or reward processes. Here, the focus is on the hippocampus which has been largely ignored in the addiction literature as compared to the nucleus accumbens (NAc), ventral tegmental area (VTA), and prefrontal cortex (PFC). The results show that METH administered unilaterally via a microdialysis probe to rats' right dorsal hippocampus will induce drug-seeking (place preference) and drug-taking (lever-pressing) behavior. Furthermore, both of these responses are dependent on local dopamine (DA) receptor activation, as they are impaired by a selective D(1)/D(5) receptor antagonist. The results suggest that the hippocampus is part of the brain's reward circuit that underlies addiction.

Ionizing radiation impairs the formation of trace fear memories and reduces hippocampal neurogenesis.

Long-term cognitive impairments are a feared consequence of therapeutic cranial irradiation in children as well as adults. Studies in animal models suggest that these deficits may be associated with a decrease in hippocampal granule cell proliferation and survival. In the present study the authors examined whether whole brain irradiation would affect trace fear conditioning, a hippocampal-dependent task. Preadolescent (postnatal Day 21, PD 21), adolescent (PD 50), and postadolescent (PD 70) rats received single doses of 0 Gray (Gy), 0.3 Gy, 3 Gy, or 10 Gy whole brain irradiation. Three months after radiation treatment, a significant dose-dependent decrease in bromo-deoxyuridine positive cells was observed. Irradiation produced a dose-dependent decrease in freezing in response to the conditioned stimulus in all age groups. Interestingly, the authors found no differences in context freezing between irradiated and control groups. Further, there were no differences in delay fear memories, which are independent of hippocampus function. Our results strongly indicate that irradiation impairs associative memories dependent on hippocampus and this deficit is accompanied by a decrease in granule cell neurogenesis indicating that these cells may be involved in normal hippocampal memory function.

Differences in performance between Sprague-Dawley and Fischer 344 rats in positive reinforcement tasks.

This experimental investigation tested two different strains of rat, Sprague-Dawley (SD) and Fischer 344 (F344), in their ability to learn lever pressing for food (autoshaping) or intracranial self-administration (ICSA) of dextroamphetamine (AMPH) into the nucleus accumbens (NAcc). Additionally, a unique method of intracranial drug delivery was utilized, via reverse dialysis, by the use of a microdiaylsis probe. The experiments revealed definite behavioral differences between SD and F344 animals. The autoshaping data indicated that SD rats, on average, acquired lever pressing for food in fewer training days than F344 rats. Also, the ICSA experiment revealed that SD rats self-administered AMPH at a 30 mug/mul concentration. Lever pressing was significantly greater in those SD rats receiving AMPH than in the F344 drug group. Furthermore, the F344 rats never acquired lever pressing for intra-NAcc delivery of AMPH under our testing regime. These data reveal differences in performance of positively reinforced operant tasks between the inbred F344 rats as compared to the outbred SD strain.

The cannabinoid CB1 receptor antagonist AM251 does not modify methamphetamine reinstatement of responding.

Cannabinoid CB(1) receptor antagonists can decrease methamphetamine self-administration. This study examined whether the CB(1) receptor antagonist AM251 [N-(piperidin-1-yl)-5-(4-indophonyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide] modifies reinstatement in rats that previously self-administered methamphetamine. Rats (n=10) self-administered methamphetamine (0.1 mg/kg/infusion) under a fixed ratio 2 schedule. Non-contingent methamphetamine (0.01-1.78 mg/kg, i.v.) yielded responding for saline (reinstatement) that was similar to responding for self-administered methamphetamine. AM251 (0.032-0.32, i.v.) did not affect methamphetamine-induced reinstatement but significantly attenuated Delta(9)-tetrahydrocannabinol (2.0 mg/kg, i.p.)-induced hypothermia. These data fail to support a role for endogenous cannabinoids or cannabinoid CB(1) receptors in reinstatement and, therefore, relapse to stimulant abuse.

Gene expression changes in the rodent hippocampus following whole brain irradiation.

Therapeutic cranial irradiation may result in debilitating cognitive impairments. In human patients these deficits are age and radiation dose-dependent and are attributed to a diminished capability to learn and memorize new tasks and information. Because of the known involvement of the hippocampus in memory consolidation, it is important to identify irradiation-induced changes including alterations in gene expression in this structure. Whole brain irradiation doses of 0, 0.3, 3, 10, or 30 Gray (Gy) were administered to 3-month-old rats in a single session. Twenty-four hours following cranial irradiation, hippocampi were processed for oligonucleotide microarrays analysis. Metallothioneins (MT)-I and -II, heat shock protein (Hsp-27), glial fibrillary acidic protein alpha (GFAP), and c-Fos genes were altered significantly across the various doses of irradiation. A pathway analysis shows that these genes were centered around the immediate early gene myc and tumor suppressor gene (TP53). Our results identified important genes and possible pathways that are altered in the hippocampus in the acute phase following cranial irradiation, and implicate gene pathways important for both learning and memory and apoptosis.

Differences in the magnitude of long-term potentiation produced by theta burst and high frequency stimulation protocols matched in stimulus number.

Theta-burst stimulation (TBS: four pulses at 100 Hz repeated with 200 ms inter-burst-intervals) and another commonly used high-frequency stimulation protocol (HFS: 1 s burst of equally spaced pulses at 100 Hz) were compared for the magnitude of LTP produced in rat hippocampal slices. The total number of pulses applied during tetanus (TET) was either 40, 100, 200, or 300. In a conventional analysis of the last 10 min of the post-TET period, a two-way ANOVA revealed no difference either in LTP of the field excitatory post-synaptic potential (fEPSP) between TBS and HFS or differences across pulse number at 40, 100, or 200 pulses. At 300 pulses, there was a significant main effect by pulse number but not by protocol. A linear regression analysis showed that stimulation protocol accounted for only about 10% of the change in magnitude while pulse number contributed to 30% of the change. However, when an extended analysis of the same data was performed across the entire post-TET period with a repeated-measure ANOVA, a small but persistent increase in TBS over HFS at 200 pulses was significant. A difference between TBS and HFS at 300 pulses that occurred only during the early phase of LTP was also significant. These results suggest that, over a range of stimuli, the number of pulses in an induction protocol, rather than the pattern of stimulation, determines the magnitude of late phase LTP, while TBS produces greater potentiation than HFS in the early phase of LTP with higher TET number.

Metabotropic glutamate receptor antagonist AIDA blocks induction of mossy fiber-CA3 LTP in vivo.

Metabotropic glutamate receptors (mGluR) are implicated in long-term memory storage. mGluR-I and mGluR-II antagonists impede various forms of learning and long-term potentiation (LTP) in animals. Despite the evidence linking mGluR to learning mechanisms, their role in mossy fiber-CA3 long-term potentiation (LTP) is not yet clear. To explain the involvement of mGluR-I in memory mechanisms, we examined the function of the mGluR-I antagonist 1-aminoindan-1, 5-dicarboxylic acid (AIDA) on the induction of mossy fiber-CA3 LTP in vivo in male Sprague Dawley and Fischer 344 (F344) rats. Acute extracellular mossy fiber (MF) responses were evoked by stimulation of the MF bundle and recorded in the stratum lucidum of CA3. The excitatory postsynaptic potential (EPSP) magnitude was measured by using the initial slope of the field EPSP slope measured 2-3 ms after response onset. After collection of baseline MF-CA3 responses at 0.05 Hz, animals received either ((+/-))-3-(2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid (N-methyl-D-aspartate-R antagonist, 10 mg/kg ip), naloxone (opioid-R antagonist, 10 mg/kg ip), or AIDA (mGluR antagonist, 1 mg/kg ip or 37.5 nmol ic). LTP was induced by two 100-Hz trains at the intensity sufficient to evoke 50% of the maximal response. Responses were collected for an additional 1 h. AIDA blocked induction of LTP in the mossy fiber pathway (P < 0.05) in both strains of rats after systemic and in Sprague Dawley rats after intrahippocampal injection.

Role of hippocampal CA3 mu-opioid receptors in spatial learning and memory.

The dorsal CA3 region of the hippocampus is unique in its connectivity, sensitivity to neurotoxic lesions, and its ability to encode and retrieve episodic memories. Computational models of the CA3 region predict that blocking mossy-fiber and/or perforant path activity to CA3 would cause impairments in learning and recall of spatial memory, respectively. Because the CA3 region contains micro-opioid receptors and receives inputs from the mossy-fiber and lateral perforant pathways, both of which contain and release opioid peptides, we tested the hypothesis that inactivating micro-opioid receptors in the CA3 region would cause spatial learning and memory impairments and retrieval deficits. In this study, male Sprague Dawley rats were trained in a Morris water maze after a single bilateral intrahippocampal injection of either saline or the selective and irreversible micro-opioid receptor antagonist beta-funaltrexamine (beta-FNA) into area CA3. We found that micro-opioid receptor binding decreased 24 hr after beta-FNA injection and returned to control levels 11 d after injection. Injections of beta-FNA into the CA3 region, but not into the ventricles, caused a significant impairment in the acquisition of spatial learning without causing sensory or motor deficits. New learning was not affected once micro-opioid receptor levels replenished (>11 d after injection). In pretrained animals, beta-FNA significantly impaired spatial memory retrieval and new (reversal) learning. These data are consistent with theoretical models of CA3 function and suggest that CA3 micro-opioid receptors play an important role in the acquisition and retrieval of spatial memory.

Flow cytometric study of neutrophilic granulopoiesis in normal bone marrow using an expanded panel of antibodies: correlation with morphologic assessments.

Flow cytometry studies of surface markers of neutrophils have been performed mostly on peripheral blood, and for a limited spectrum of diseases. Studying maturation defects on developing neutrophils in the bone marrow (BM) may be helpful in BM diseases, such as myelodysplastic syndromes and Shwachman-Diamond syndrome. We applied an expanded panel of antibodies to examine normal maturation patterns in 26 control samples of BM together with microscopic correlation. Promyelocytes correlated well with the CD24(-) and CD11b(-) populations, and metamyelocytes correlated well with the CD16(+) population (intermediate positivity). An excellent correlation was also identified between the sum of bands and segmented neutrophils and each of the following: CD16(++) (strong positivity), CD35(+), CD87(+), and CD64(-). Although visually identified segmented neutrophils paralleled CD10 positivity, there was an appreciable difference between both methods. We conclude that neutrophilic granulocyte maturation in the BM is accompanied by a change in surface antigens that reflects certain stages of development. A successful strategy for detecting maturation defects is to include several antibodies that are known to be expressed or absent at the same stage of maturation, such as CD16, CD35, CD64, and CD87.